This invention relates to heat exchangers which are for carrying out heat exchange between fluids, such as gas or a liquid.
In order to carry out heat exchange between a first and a second fluid, a conventional heat exchanger comprises a tube and a plurality of fins mounted on an outer surface of the tube. The fins are for contacting with the first fluid flowing through gaps between the fins. The tube is for conducting the second fluid therethrough.
The first fluid generally flows with a flow energy distribution within a lateral section of the flow thereof. In the flow energy distribution, it is assumed that the first fluid has portions which are different from one another in flow energy. This results in reduction of efficiency of the heat exchange in comparison with a case where the first fluid would have a uniform flow energy within the section of the flow.
In order to improve the efficiency of the heat exchange, various heat exchangers of the type are already known. A known heat exchanger is disclosed in, for example, JP-A-60-175992.
In the known heat exchanger, a tube is formed in a serpentine-anfractuous shape to have a plurality of tube portions arranged parallel with one another with spaces left therebetween. Fins are formed to have a thickness and are disposed in each of the spaces. The spaces are designed with reference to the flow energy distribution and therefore one of the spaces is different in size from another. However, it is difficult to manufacture the heat exchanger because the tube must be bent to define spaces of different sizes.
JP-A-60-175992 also discloses another example of the heat exchanger wherein fin pitches are designed different between a fin set portion and another fin set portion with reference to the flow energy distribution. However, it is difficult to manufacture the heat exchanger because it is very complicated to fix the fins onto the tube with various fin pitches.
Another heat exchanger is disclosed in JP-U-63-5270, wherein fins extend in a flowing direction of the first fluid with different extensions from one another with reference to the above-mentioned flow energy distribution. However, this results in reduction of ability of the heat exchange in the heat exchanger.